Prior control mechanisms include reciprocating knives which support and displace all of the associated heald rods at all times, until a rod is selected. When a rod is selected, it is supported independently of the reciprocating knives, for example as shown in U.S. Pat. Nos. 4,739,806 and 5,176,186. Since all heald rods except those selected are in continual motion during shed formation, there is considerable wear on the heald rod guide and harness pulleys and the knives are subject to continuous loading.